Hand microphone for sound transducing appliances



Apnl 19, 1960 w. MULLER ET AL 3 HAND MICROPHONE FOR SOUND mnsnucmc APPLIANCES Filed April 30, 1957 3 Sheets-Sheet 1 l/I'A Y A/VHLLER MD 0770 6411.05

A, yams.

April 1 9 0 w. MULLER ET AL 2,933,566

HAND MICROPHONE FOR SOUND TRANSDUCING APPLIANCES Filed April 30, 1957 5 Sheets-Sheet z 32 38 35 27 4 I Q 30 3.9 21k: 20 I /-w:--roas Msm April 19, 1960 w. MULLER ET AL 2,933,566

HAND MICROPHONE FOR SOUND TRANSDUQING APPLIANCES Filed April 30, 1957 3 Sheets-Sheet 3 Fi 40 my United States PatentO Zurich, Switzerland, and Otto Holub, Dachau, Germany; said Holub assignor to said Miiller Application April 30, 1957, Serial No. 656,106

Claims priority, application Switzerland December 19, 1956 3 Claims. (Cl. 179-167) The invention relates to a hand microphone for sound transducing appliances which is provided with switch means for switching the said sound transducing appliance to recording, reproduction or repetition operational conditions.

It is a main object of the present invention to provide a hand microphone of the kind referred to wherein the inadvertent switching-on of two different conditions of the said sound transducing appliance is safely obviated.

It is another object of the invention to provide a hand microphone of the kind referred to which is simple, does not occupy much space, lends itself to being laid flat on a table top or the like, and to being economically mass produced.

With these and other objects in view we provide a hand microphone for a sound transducing appliance comprising in combination: a casing, a microphone capsule and a remote control switch both arranged in said casing, and electrical leads connecting the said microphone capsuie and the said switch with one another and with the said sound transducing appliance, the said switch having three working positions connecting the said sound transducing appliance for recording, reproduction and repetition, respectively, and a rest position switching the said sound transducing appliance off, each of the said working positions being attainable only from the said rest position.

' These and other objects and features will be clearly understood from the following description of a preferred embodiment thereof given by way of example with reference to the accompanying drawings, in which:

Fig. 1 is a plan view of the hand microphone,

Fig. 2 is a longitudinal section thereof,

Fig. 3 shows the switch on an enlarged scale in a longitudinal section corresponding to Fig. 2,

Figs. 4a and 4b show the switch in the rest position, from below and above, respectively, with the omission of some components,

Figs. 5a and 5b correspond to Figs. 4a and 4b but show the repetition position, while Figs. 6a and 6b correspond to Figs. 4a and 4b but show the reproduction position.

The casing of the microphone illustrated consists of two parts 1 and 2, which are connected to one another by screws 3. The rear face of the casing part 1 is fiat in order to permit the microphone to lie flat on a table top or the like. On a base plate 4 a remote control switch 5 is mounted by means of three screws 6. Adjacent the control knob 7 of the switch 5 three working positions are marked on the frontal face of the upper casing part 2, A denoting the recording position, W the reproducing position and R the repetition position. Instead of letters other markings could be provided, e.g. coloured dots.

Between the microphone capsule 8 and the base plate 4 there is arranged a slide switch 9 the knurled finger grip 10 of which is slidable in a recess 11 of the casing part 1, without protruding beyond the flat rear face thereof. This switch 9 serves for switching in the usual manner a damping resistor 12 connected either in parallel or in series with the microphone capsule 8. The leads 13 starting from the microphone capsule pass into a cable 14 which serves to connect the hand microphone to the sound recording and reproducing appliance. This cable moreover contains four leads 15 which lead to the contact springs 16A, 16W, 16R and 17, respectively, of the remote control switch 5. The contact springs 16A, 16W and 16R project through slots 18 mutually offset of a ring 19 into the interior of the latter. The ring 19 is fixed by means of the aforesaid screws 6 with one end face to the base plate 4, these screws serving also for the attachment of a guide plate 20 to the other end face of the ring.

From the centre of the guide plate 20 three guide slots 21A, 21W and 21R provided therein radiate, mutually offset 120. In these slots a screw-threaded bolt 22 is slidable to the outer end of which the knob 7 is screwed. The screw-threaded bolt 22 has a collar 23 which is not threaded. On the inner end of the screw-threaded bolt 22 a. bushing 25 is screwed, which carries a contact disc 26. On the bushing 25 moreover a guide disc 27 is screwed which lies at one side of the guide plate 20. At the other side of this guide plate lies a second guide disc 28 which is loosely pushed over the bushing 25 and is subject to the action of a compression spring 29, which abuts against the contact disc 26. Under pressure of the spring the discs 27 and 28 contact the guide plate 20 without play so that the bolt 22 always remains perpendicular to the plate 20 when being shifted in the slots 21A, 21W or 21R. 7

On the screw 6 shown in Fig. 3 a stepped bushing 30 is mounted which serves as a pivot for a pawl 31 pivotally mounted thereon and having a slot 32 likewise engaged by the screw-threaded bolt 22. The two prongs 33 of the pawl 31 on both sides of the slot 32 are chamfered to a wedge shape (see for example Fig. 41:). A eaf spring 34 is attached to a holder 35 which is in turn mounted on the ring 19 by means of one of the screws 6. The arcuate free end 36 of the leaf spring 34 serves to arrest the pawl 31 in that it cooperates with the wedge-shaped, chamfered tips thereof.

In the upper casing part 2 there are provided three slots 37 angularly spaced 120 apart and corresponding to the slots 21A, 21W and 21R of the guide plate 20, but slightly wider than they in accordance with the diameter of the collar 23 guided therein. The switch knob 7 is so proportioned at its base that in the rest position it covers the slots 37 completely, and may do so even when shifted into any one of the three working positions. On the upper casing part 2 moreover an inwardly directed projection 38 of semiannular shape is provided, which has a shoulder 39 in which engages the switch 5 with its guide plate 20. Two inwardly projecting, symmetrically disposed longitudinal ribs 40 of the upper casing part 2 serve as an abutment for the microphone capsule 8 so that the latter, together with the switch 9, the base plate 4, the remote control switch 5 and all other internal components can be simply inserted between the casing parts 1 and 2 so as to be held in position by the casing. With 41 a fabric sieve is denoted which is visible in Fig. 1 through five slots 42 which are provided in the upper casing part 2 in order to let the sound reach the microphone capsule 8.

The remote control switch 5 operates as follows: The contact spring 17 is permanently in contact with the contact disc 26, as can be seen particularly in Fig. 3. In the rest position (see Figs. 4a and 4b) the contact disc 26 does not engage any one of the contact springs 16A, 16W and 16R.

, 3 When, by means'of the knob 7, the bolt 22 is shifted into the slot 21R, the contact disc 26 engages the contact spring 16R (see Figs. 5a and 5b) so that the contact springs 17and 16R are conductively connected to one another. Thereby the sound transducing appliance is switched in the usual way to repetition. When the knob 7 is released in this working position, it returns automatically to the rest position under the action of the tension spring 24. The pawl 31 is releasably retained in a normal, rest position as well as in the repetition position by the arcuate end 36 of the leaf spring 34, which contacts the inner wedge faces of the two prongs of the end of the leaf spring 36 comes into contact with the outer wedge face of a prong 33 of the pawl. Consequently, an automatic swinging-back of the pawl 31 into its rest position is thereby prevented by spring 34, and the switch 5 remains in the reproduction position, until the knob 7 is restored to its rest position, against the restraint of spring 34.

When shifting the bolt 22 into the slot 21A, the contact disc 26 engages the contact spring 16a, and the sound transducing appliance is switched to recording. This position is not illustrated in the drawing since it is identical to but opposite that of Figs. 6a and 6b.

The knob 7 can be conveniently shifted by the thumb. Any double switching is completely excluded, and moreover one can get from one working position into another only through the rest position.

The simplicity of the design described permits a very economical mass production of this hand microphone.

While we have described herein and illustrated in the accompanying drawings what may be considered a typical and particularly useful embodiment of our said invention we wish it to be understood that we do not limit ourselves to the particular details and dimensions described and illustrated, for obvious modifications will occur to a person skilled in the art.

What we claim as our invention and desire to secure by Letters Patent is:

1. In a hand microphone for a sound transducing appliance a remote control switch having three working positions for connecting the sound transducing appliance for recording, reproducing-and repeating, respectively, and a rest position for switching said appliance 00?, said switch comprising, a casing, a guiding member having guide slots radiating from a center corresponding to said rest position in three angularly spaced directions corresponding to said working positions, respectively, a control member including a knob and a bolt secured to said knob, said bolt being shiftable from said rest position along said guide slots into any one of said working positions, a return spring operatively connected both to said bolt and to said casing and biasing said bolt automatically from the said repetition position back to said rest position whenthe control knob is released, and locking means detaining the said bolt in said reproducing and recording positions, respectively, the control knob when operated overriding said locking means.

2. A device as in claim 1, wherein the locking means comprises a two-pronged pawl pivotally mounted in the casing, the prongs of said pawl being chamfered to a wedge shape, and a leaf spring attached at one end to the casing and having a second arcuate end engaging said prongs, the prongs of the pawl embracing said bolt and the arcuate end of the leaf spring contacting the inner wedge faces of the prongs in said rest and repetition positions, and contacting the outer wedge faces of one of said prongs in said recording and reproducing position.

3. A device as in claim 1, wherein said guiding member is a guide plate fixed to said casing, said switch further comprising a contact disc secured to said bolt at its end opposite said knob, two guide discs attached to said bolt on both sides of said guide plate and contacting the same slidably, said guide discs holding said bolt perpendicular'to said guide plate in any of said working positions and in said rest position, and a compression spring abutting against one of said guide discs and against said contact disc.

7 References Cited in the file of this patent UNITED STATES PATENTS 

